Fluid-pressure tool



April 12, 1927. 1,624,179

E. PENBERTHY FLUID PRESSURE TOOL Filed Jan. 27. 1925 vlsm/zrro/P/vsy 4 @(M Patented Apr. 12, 192?. Y

UNITED STATES PATENT oFFicE.

ERNEST PENBERTHY, OI DETROIT, MICHIGAN, ASSIGNGB T CHICAGO PNEUMATIC TOOL COMPANY, OF I-IElV YORK, N. Y., A GGRPORATION OF NEVT JERSEY.

FLUID-PRESSURE TOOL.

Application filed January This invention relates to fluid pressure tools having a two diameter piston or impact member providing two pressure areas for driving the piston in one direction and one pressure area for ret-ur the same, one oi the forward pressure areas being continuously subjected to the motive fluid. It is particularly concerned with the manner and means of automatic control of the motive lluid to the two intermittent pressure areas of the piston. lVhile the invention is especially adapted and intended for drills used in stoping it is by no means confined thereto but is also applicable to drills for drifting and sinking. and for drilling and mlnmg operations in general.

Among the objects of the invention are to provide a drill of the described type characterized by high piston speed, full piston stroke. and positive and reliable operation. and in general to improve prior drills of this type.

The invention has to do with fluid pressure percussive tools, hammers and hammer drills. commonly referred to as semi-valveless with particular reference to the valve action thereof and the manner in which the motive fluid is admitted to and exhausted from the pressure areas of the piston to secure the above objects.

In order to make clear the nature of the invention concrete embodiments thereof are shown in the accompanying drawings in which:

Fig. l is a longitudinal sectional view through a stoper embodying the invention;

Fig. 2 a view similar to l 1 but shovving the operative parts in a different position; and

Fig. 3 is a view similar to Fig. 1 showing a slightfymodiiied form of the invention.

()t' the embodiments of the invention chosen for the purpose of illustration each comprise a fluid pressure operated tool havi: a casing or cylinder 4; provided with a front head 5 to receive the shank end of the working tool or drill steel 6. the latter being arranged to receive the blows ot the impact member or piston 7 either directly or through an anvil block 8 which may be supported in a guide member 9 interposed between the front head 5 and the cylinder 4:.

For use in stoping work to which the invention is particularly adapted the cylinder 27, 1925. Serial No. 5,002.

it may have secured thereto in any known or suitable manner the usual feed cylinder 10 in which a piston 11 on the piston rod 12 is arranged "for sliding movement under the impulse of motive fluid which may be admitted to the feed cylinder through a pas- 13 by a proper setting on the throttle valve 14.

Referring now to the impact member or piston 7 and the means for automatic con trol of the movement of the same it will be noted that the piston comprises a head 7 slidably fitted in the large bore 15 ot the piston chamber and provided with a rearwardly extending projection or stem 7 of reduced diameter slidably fitting the reduced bore 15 or" the piston chamber. The head 7 opens and closes during its reciprocation a main exhaust port 16 in cylinder 4;, this exhaust port with its connecting passage 16 being alternately placed in communication with the space before and behind the head 7. Stem 7" of the piston controls an annular port 17 from which extends a passage 17 opening into the piston chamber bore 15 in advance of the forward position of the head 7.

One of the pressure areas of the piston 7 for driving the same forwardly. namely the end of its stem 7 is continuously subjected to motive fluid admitted to the live air chamber 18 of the cylinder 4: by the throttle alve 14 when the drill is in operation. The front and rear faces of the piston head 7* form intermittent pressure areas alternately'open to the exhaust port 16. motive fluid being conducted to the forward or largest pressure area by passage 17%. when piston stem 7 opens annular port 17 near the end of the forward stroke of the piston (F 2). The supply of motive fluid to the second intermittent pressure area of the valve, namely the rear face of the head 7 is controlled by an automatic valve 19 ar-' ranged for ii'eciproca'tory movement in a valve chamber 20. Valve 19 is of the spool type with end heads of equal diameter the rearmost of which controls an annular port 21 communicating with a. passage 21 leading to the live air chamber 18. lVhen the valve is in its rearmost position (Fig. 1) port 2lis in communication with the central chamber formed by the reduced central portion of valve 19 and thence with a pas sage opening into an annular port 22- at the rear of the large bore 15 of the pis ton chamber and directly against the rear face of head 7 of the piston. lVhen valve 19 shifts to its forward position (Fig. 2) live air port 21 is closed and an auxiliary exhaust port 23 communicating with atmosphere is placed in communication with passage 22.

Value 19 is shifted from its rearward po sition (Fig. 1) to its forward position (Fig. 2) when piston stem 7 uncovers port 17 through a branch passage 17 which admits motive fluid directly against the rear head of valve 19 which may be hollowed out or made cup shaped as shown if desired. The shifting of the valve in the reverse direction is accomplished by a built up pressure against the other or forward head of the valve. To this end a small radial port :21 in the rear head of valve 19 so disposed as to be always in register with live air port 21 admits live air in limited amount to an axial bore 25 in the valve opening into the forward end of the valve chamber. From this end of the valve chamber leads a vent passage 26 which opens into the large bore 15 of the piston chamber near its rearward end. By this arrangement the stream of live air continuously admitted to the forward end of the valve chamber by passages 2 1 and 25 in the valve passes into the piston chamber without causing any motion of the valve until vent passage 26 is closed by the piston head 7 a near the end of its rearward stroke whereupon the pressure builds up against the forward end of the valve and shifts the latter the other end of the valve being meanwhile opened to exhaust by the uncovering of exhaust port 16 as the piston head 7 passes beyond the same.

The operation of the motor is as follows: lVith the parts in the position shown in Fig. 1 the piston is beginning its forward stroke with the pressure fluid continuously in con tact with the end of the piston stem 7" and also acting against the rear face of piston head 7 from passages 21, port 21, the valve chamber and passage 22. while the front end of the piston chamber is open to exhaust through port 16. As the piston passes beyond the exhaust port 16 (Fig. 2) and exhausts the pressure [luid which has hereto fore been acting against the rear face of head 7, the stem 7" opens port 17 to the motive fluid in live air chamber 18 which flows into passages 17 and 17 shifting the valve and starting the piston on its back stroke. As the piston begins its back stroke the stem 7 closes port 17 whereupon the rearward movement of the piston is continued by the expansion of air in the front of bore 15 augmented by live pressure admitted in a manner presently to be described. As piston head 7 crosses main exhaust 16 the air trapped behind or to the right of the piston head continues to escape through the auxiliary valve control exhaust comprising passage 22, the valve chamber and the valve controlled exhaust port lVhen the pis ton passes beyond exhaust 16 and relieves the pressure on the rear end of valve 19 and through passages 17 and 17". it also closes at the same time vent port 26 whereupon the pressure builds up against the front end of the valve shifting it to its original position 1) whereupon the cycle of opera tions is repeated.

In order to secure full drilling power piston 7 should make a full rearward stroke. Even with the auxiliary valve controlled exhanst 23 relieving the pressure trapped behind the piston head 7 a longer admission of motive fluid to the front of the piston chamber is necessary by reason of the continuous pressure of motive fluid against the end of the piston stem. One arrangement for accomplishing this is illustrated in Figs. 1 and 2 wherein a branch passage 27 leads from the live air passage 21 to a port 28 controlled by the rear head of the valve. \Vhen the piston is making its forward stroke (Fig. 1) port 28 is closed by the valve but when the. valve shifts (F ig. 2) the port 25 is opened admitting live motive fluid in limited amount to passages 17", 17 and to the front end of the piston chamber to continue the rearward movement of the piston after its stem has closed port 17 this admission of air continuing until the valve shifted. Fig. 3-3 shows a slightly modified manner of accon'iplishing the same results wherein the valve controlled port 28 bears a similar relation to the valve as port 28 of l igures l and 2 but its communicating p *age 27 leads to the smaller piston bore 15 conimunicating with the latter by an annular port- 27" whereby the passage 27 is piston. controlled. \l'ith this arrangement motive fluid continues to pass to the front of the piston chamber from chamber is through port 27", passage 27. port 28 and pa sages 17" and 17* while the piston stem moves from port 17 to and closes port 27, expansion of the motive fluid previously admitted and momentum of the piston being thereafter rclied upon to cause a full rearward stroke of the piston.

From the aoove it will be apparent that the short throw of the valve together with distributing and control of the motive fluid provided by the present invention insures high piston speed and full piston stroke.

1 claim as my invention:

1. In combination in a fluid pressure percussive tool having a cylinder. a hammer piston reciprocable therein having two pressure areas for driving it in one direction and an opposed pressure area for returning it, one of said first named areas being continulllll Ill) Ill)

ously subjected to pressure fluid and the other areas to intermittent pressure, said piston controlling a main exhaust port for both said intermittent areas and also a supply passage to one of said intern'iittent areas, a valve controlling the supply of motive fluid to the other of said intermittent pres sure areas, said valve being shifted in one direction when said supply passage is uncovered by said piston, a passage continuously supplying motive fluid in limited amount to one end of said valve, and a vent passage -from said end of said valve controlled by said piston whereby a built up pressure shifts the valve in the opposite direction.

2. In combination in a fluid pressure percussive tool having a cylinder, a hammer piston reciprocable therein having two pressure areas for driving it in one direction and an opposed pressure area for returning it, one of said tirst named areas being continuously subjected to pressure fluid and the other areas to intermittent pressure, said piston controlling a main exhaustport for both said intermittent areas and also a supply passage to one of said intermittent areas, a valve controlling the supply Of motive fluid to the other of said intermittent pres sure areas, said valve being shifted in one direction when said supply passage is uncovered by said piston, a passage extending through said valve supplying motive fluid continuously in limted amount to one end thereof, and a vent passage from said end of said valve controlled by said piston whereby a. built up pressure shifts the valve in the opposite direction.

3. In combination in a fluid pressure percussive tool having a cylinder, a hammer piston reciproeable therein having two pressure areas for driving it in one direction and an opposed pressure area for returning it,

one of said first named areas being con tinnously subjected to pressure fluid and the other areas to intermittent pressure, said piston controlling a main exhaust port .lor both said intermittent areas and also a sup ply to one of said intermittent areas, and a valve controlling the motive fluid supply to the other of said intermittent areas, said valve being shifted in one direction by pressure admitted thereto by said piston and in the other direction by a built up pressure.

t. In combination in a fluid pressure percussive tool having a cylinder, a hammer piston rcciprocablc therein having two pressure areas "for driving it in one direction and an opposed pressure area for returning it, one of said first named areas being continuously subjected to pressure fluid and the other areas to intermittent pressure, said piston controlling a main exhaust port 'for both said intermittent areas and also a supply to one of said intermittent areas, and a val vc controlling the motive fluid supply to the other of said intermittent areas, and also controlling an auxiliary exhaust therefor,

5.111 combination in a fluid pressure.

percussive tool, having a cylinder, a two diameter hammer piston reciprocable therein having two pressure areas for efiecting its forward strokes and a single area for its rearward stroke, one of said forward pressure areas being continuously subjected to motive fluid and the remaining areas to intern'iittent pressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston controlled passage for the motive fluid supply to the other or return intermittentarea of the piston, and means controlled by said valve, for continuing the admission of motive fluid to said last named area at'ter said passage has been closed by said piston.

6.111 combination in a fluid pressure percussive tool, having a cylinder, a two diameter hammer piston reeiprocable therein having two pressure areas for efl'ecting its forward strokesand a single area for its rearward stroke, one of said forward pressure areas being continuously subjected to motive fluid and the remaining areas to intermittent )ressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston controlled passage for the motive fluid supply to the other or return intermittent area of the piston, and means controlled by said valve, for coi'it nuing the admission of motive fluid to said last named area after said passage has been closed by said piston, said valve being shifted in one direction when said passz'ige is uncovered by said piston on its forward stroke.

7. In combination in a fluid pressure percussive tool, having a cylinder a two diameterhammer piston .reciprocable therein having two pressure areas for effecting its i'orward stroke and a single area for its rearward stroke, one ot'said forward pressure areas being continuously subjected to motive fluid and the remaining areas to i..ntermittent pressure, a valve controlling the motive fluid supply to the forward intermittent area oi the piston, a piston controlled passage tor the motive i'luidsupply to the other or return intermittent area oi the piston, means controlled by said valve for continuing the admission of motive fluid to said last named area after said passage has been closed by said piston, and means for ett'ccting shitting ot' thevalvc subsequent to the closing of said passage by said piston 8. In combination in a fluid pressure percussive tool having a cylinder, a two diameter hammer piston reciprocable therein having two pressure areas for etl'ecting its foriii) ward stroke and a single area for its rearward stroke. one of said forward pressure areas being continuously subjected to motive fluid and the remaining areas to intermittent pressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston controlled passage for the motive fluid supply to the other or return intermittent area of the piston, means controlled by said valve for con tinuing the admission of motive fluid to said last named area after said passage has been closed by said piston. and means controlled by said piston for effecting shifting of the valve subsequent to the closing of said passage by said piston.

9. In combination in a fluid pressure percussive tool having a cylinder, a two diam-,

eter hammer piston reciprocable therein having two pressure areas for effecting its forward stroke and a single area for its rearward stroke, one of said forward pressure areas being continuously subjected to motive fluid and the remaining areas to intern'iittent pressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston controlled passage for the motive fluid supply to the other or return intermittent area of the piston, means cont-rolled by said 'alve for continuing the admission of motive fluid to said last named area after said passage has been closed by said piston, said valve being shifted to permit said admission on the uncovering of said passage by said piston on its forward stroke, and means controlled by said piston for utilizing a built up pressure to shift said valve to stop said admission near the end of the rearward stroke of said piston.

"10.111 combination in a fluid pressure percussive tool having a cylinder. a. two diameter hammer piston reciprocable therein having two pressure areas for effecting its forward stroke and a single area for its rearward stroke, one of said forward pressure areas being continumisly subjected to motive fluid and the remaining areas to intermittent pressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston con trolled passage for the motive fluid supply to the other or return intermittent area of the piston, means controlled by said valve for continuing the admission of motive fluid to said last named area after said passage has been closed by said piston, said valve being shifted to permit said admission on the urn covering of said passage by said piston on its forward stroke, and means for shifting the valve in the reverse direction to stop said admission by a built up pressure comprising a passage continuously admitting motive fluid in limited amount to a pressure area of said valve and a vent passage leading from said area. to the piston chamber and arranged to be closed by said piston near the end of its rearward stroke.

11. In combination a fluid pressure percussive tool having a cylinder, a. two diameter piston reciprocable therein having two pressure areas for effecting its forward stroke and a single area for its rearward stroke, one of said forward pressure areas being continuously subjected to motive fluid and the remaining areas to intermittent pressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston controlled passage from the motive fluid supply to the other or return intermittent area of the piston, means controlled jointly by said valve and said piston for continuing the admission of motive fluid to said last named area after said passage has been closed by said piston, said valve being shifted to permit said admission on the uncovering of said passage by said piston on its forward stroke, and means controlled by said piston for utilizing a built up pressure to shift said valve to stop said admission near the end of the rearward stroke of said piston.

12. In combination in a fluid pressure percussive tool having a cylinder, a two diameter piston rec-iprocable therein having two pressure areas for effecting its forward stroke and a. single area for its rearward stroke, one of said for aid pressure areas being continuously subjected to motive fluid and the remaining areas to intermittent pressure, a valve controlling the motive fluid supply to the forward intermittent area of the piston, a piston controlled passage for the motive fluid supply to the other or return intermittent area of the piston, means for continuing the admission of motive fluid to said last named area after said passage has been closed by said piston comprising a second passage controlled by said piston and arranged to be connected to said first passage bysaid valve, said valve being shifted to permit said admission on the uncovering of said. first passage by said piston on its forward stroke, and means controlled by said piston for producing reverse movement of said valve after said piston has closed both said first and second passages.

Signed by me at Detroit, ldiclr, this 20th day of January, 1925.

ERNEST IENBERTHY. 

